CN114800943B - Method for recycling waste carpets - Google Patents
Method for recycling waste carpets Download PDFInfo
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- CN114800943B CN114800943B CN202210554923.6A CN202210554923A CN114800943B CN 114800943 B CN114800943 B CN 114800943B CN 202210554923 A CN202210554923 A CN 202210554923A CN 114800943 B CN114800943 B CN 114800943B
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- Prior art keywords
- nylon
- carpet
- solvent
- choline chloride
- carpets
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- 239000002699 waste material Substances 0.000 title claims abstract description 44
- 238000000034 method Methods 0.000 title claims abstract description 36
- 238000004064 recycling Methods 0.000 title claims abstract description 32
- 239000000463 material Substances 0.000 claims abstract description 74
- 239000002904 solvent Substances 0.000 claims abstract description 72
- 229920001778 nylon Polymers 0.000 claims abstract description 60
- 239000004677 Nylon Substances 0.000 claims abstract description 55
- 229920000098 polyolefin Polymers 0.000 claims abstract description 41
- 239000001763 2-hydroxyethyl(trimethyl)azanium Substances 0.000 claims description 40
- 235000019743 Choline chloride Nutrition 0.000 claims description 40
- 229960003178 choline chloride Drugs 0.000 claims description 40
- 230000005496 eutectics Effects 0.000 claims description 39
- SGMZJAMFUVOLNK-UHFFFAOYSA-M choline chloride Chemical compound [Cl-].C[N+](C)(C)CCO SGMZJAMFUVOLNK-UHFFFAOYSA-M 0.000 claims description 38
- 238000011084 recovery Methods 0.000 claims description 19
- 238000001914 filtration Methods 0.000 claims description 16
- 238000001035 drying Methods 0.000 claims description 15
- 238000005406 washing Methods 0.000 claims description 15
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 14
- 239000004202 carbamide Substances 0.000 claims description 14
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical group C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 claims description 14
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 claims description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 13
- 239000004744 fabric Substances 0.000 claims description 12
- 239000000706 filtrate Substances 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 11
- 238000010992 reflux Methods 0.000 claims description 10
- 238000006243 chemical reaction Methods 0.000 claims description 6
- RLSSMJSEOOYNOY-UHFFFAOYSA-N m-cresol Chemical compound CC1=CC=CC(O)=C1 RLSSMJSEOOYNOY-UHFFFAOYSA-N 0.000 claims description 6
- IWDCLRJOBJJRNH-UHFFFAOYSA-N p-cresol Chemical compound CC1=CC=C(O)C=C1 IWDCLRJOBJJRNH-UHFFFAOYSA-N 0.000 claims description 6
- 238000004821 distillation Methods 0.000 claims description 5
- 238000005096 rolling process Methods 0.000 claims description 5
- HJJPJSXJAXAIPN-UHFFFAOYSA-N arecoline Chemical compound COC(=O)C1=CCCN(C)C1 HJJPJSXJAXAIPN-UHFFFAOYSA-N 0.000 claims description 4
- 238000001704 evaporation Methods 0.000 claims description 4
- 230000008020 evaporation Effects 0.000 claims description 4
- QWVGKYWNOKOFNN-UHFFFAOYSA-N o-cresol Chemical compound CC1=CC=CC=C1O QWVGKYWNOKOFNN-UHFFFAOYSA-N 0.000 claims description 4
- 239000002994 raw material Substances 0.000 claims description 4
- 239000002131 composite material Substances 0.000 claims description 3
- 238000010008 shearing Methods 0.000 claims description 3
- 235000013877 carbamide Nutrition 0.000 claims description 2
- 238000005374 membrane filtration Methods 0.000 claims description 2
- 238000011085 pressure filtration Methods 0.000 claims description 2
- 238000009288 screen filtration Methods 0.000 claims description 2
- 229910001220 stainless steel Inorganic materials 0.000 claims description 2
- 239000010935 stainless steel Substances 0.000 claims description 2
- 239000000725 suspension Substances 0.000 claims description 2
- 229940045136 urea Drugs 0.000 claims description 2
- 238000003828 vacuum filtration Methods 0.000 claims description 2
- 238000003912 environmental pollution Methods 0.000 abstract description 3
- 229920002292 Nylon 6 Polymers 0.000 description 20
- 229920002302 Nylon 6,6 Polymers 0.000 description 15
- 239000001257 hydrogen Substances 0.000 description 13
- 229910052739 hydrogen Inorganic materials 0.000 description 13
- 239000000835 fiber Substances 0.000 description 9
- -1 polypropylene Polymers 0.000 description 9
- 238000000926 separation method Methods 0.000 description 9
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 8
- 239000004952 Polyamide Substances 0.000 description 7
- 229960001231 choline Drugs 0.000 description 7
- 229920002647 polyamide Polymers 0.000 description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 6
- 239000004743 Polypropylene Substances 0.000 description 6
- 239000002253 acid Substances 0.000 description 6
- 230000009286 beneficial effect Effects 0.000 description 6
- 230000003993 interaction Effects 0.000 description 6
- 239000002608 ionic liquid Substances 0.000 description 6
- 238000002156 mixing Methods 0.000 description 6
- 229920001155 polypropylene Polymers 0.000 description 6
- OEYIOHPDSNJKLS-UHFFFAOYSA-N choline Chemical compound C[N+](C)(C)CCO OEYIOHPDSNJKLS-UHFFFAOYSA-N 0.000 description 5
- 238000004090 dissolution Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 229910000019 calcium carbonate Inorganic materials 0.000 description 4
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 4
- 229920003048 styrene butadiene rubber Polymers 0.000 description 4
- 150000003505 terpenes Chemical class 0.000 description 4
- 235000007586 terpenes Nutrition 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- 229920001875 Ebonite Polymers 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 238000005336 cracking Methods 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 238000009413 insulation Methods 0.000 description 3
- 239000003960 organic solvent Substances 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 239000000370 acceptor Substances 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- WNLRTRBMVRJNCN-UHFFFAOYSA-N adipic acid Chemical compound OC(=O)CCCCC(O)=O WNLRTRBMVRJNCN-UHFFFAOYSA-N 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 150000001450 anions Chemical class 0.000 description 2
- 125000006297 carbonyl amino group Chemical group [H]N([*:2])C([*:1])=O 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- JBKVHLHDHHXQEQ-UHFFFAOYSA-N epsilon-caprolactam Chemical compound O=C1CCCCCN1 JBKVHLHDHHXQEQ-UHFFFAOYSA-N 0.000 description 2
- 235000019253 formic acid Nutrition 0.000 description 2
- NAQMVNRVTILPCV-UHFFFAOYSA-N hexane-1,6-diamine Chemical compound NCCCCCCN NAQMVNRVTILPCV-UHFFFAOYSA-N 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 150000005837 radical ions Chemical class 0.000 description 2
- 239000002028 Biomass Substances 0.000 description 1
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 1
- 239000004381 Choline salt Substances 0.000 description 1
- 238000005411 Van der Waals force Methods 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000001361 adipic acid Substances 0.000 description 1
- 235000011037 adipic acid Nutrition 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 150000001335 aliphatic alkanes Chemical class 0.000 description 1
- 239000001110 calcium chloride Substances 0.000 description 1
- 229910001628 calcium chloride Inorganic materials 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 235000019417 choline salt Nutrition 0.000 description 1
- 239000008139 complexing agent Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000006184 cosolvent Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000011978 dissolution method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005518 electrochemistry Effects 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 description 1
- 239000011256 inorganic filler Substances 0.000 description 1
- 229910003475 inorganic filler Inorganic materials 0.000 description 1
- 230000007794 irritation Effects 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- 231100000053 low toxicity Toxicity 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 231100000956 nontoxicity Toxicity 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- FITXJLJVGCNARJ-UHFFFAOYSA-N phenol toluene Chemical compound C1(=CC=CC=C1)C.C1(=CC=CC=C1)O.C1(=CC=CC=C1)C.C1(=CC=CC=C1)O FITXJLJVGCNARJ-UHFFFAOYSA-N 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000000053 physical method Methods 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 150000003248 quinolines Chemical class 0.000 description 1
- 239000012047 saturated solution Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 230000000638 stimulation Effects 0.000 description 1
- 238000000967 suction filtration Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/02—Separating plastics from other materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/04—Disintegrating plastics, e.g. by milling
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B2017/001—Pretreating the materials before recovery
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B2017/001—Pretreating the materials before recovery
- B29B2017/0015—Washing, rinsing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/02—Separating plastics from other materials
- B29B2017/0203—Separating plastics from plastics
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/02—Separating plastics from other materials
- B29B2017/0213—Specific separating techniques
- B29B2017/0217—Mechanical separating techniques; devices therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/02—Separating plastics from other materials
- B29B2017/0213—Specific separating techniques
- B29B2017/0293—Dissolving the materials in gases or liquids
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/62—Plastics recycling; Rubber recycling
Landscapes
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Mechanical Engineering (AREA)
- Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
Abstract
The invention discloses a method for recycling waste carpets, which specifically comprises the following steps: (1) pretreatment of waste carpets; (2) crushing waste carpets; (3) recovering the polyolefin material; (4) recovering the nylon material; (5) recovering the solvent. The recycling method can efficiently and safely recycle the waste carpets, reduce the resource waste and reduce the environmental pollution.
Description
Technical Field
The invention relates to the technical field of high polymer recycling, in particular to a recycling method of waste carpets.
Background
With the environmental protection, green recycling economy and sustainable development advocated by society, government departments pay more and more attention to garbage classification and recycling treatment. 400-600 ten thousand tons of waste carpets are produced every year worldwide, so the recovery treatment of the waste carpets is a problem to be solved urgently.
Carpet materials are typically composed of carpet face fibers and a backing material (including a backing material, an adhesive to the backing, and an inorganic filler). Among them, nylon carpet is the chemical fiber carpet used in the earliest and large quantity, and has the advantages of wear resistance, acid and alkali resistance, high mechanical strength and the like. The waste nylon carpet mainly comprises a suede formed by nylon 6 or nylon 66 fibers, a lining formed by polypropylene and styrene-butadiene rubber adhesive filled with a large amount of calcium carbonate.
At present, the foreign nylon carpets are mainly recovered by solvent cracking and domestic mechanical crushing and cleaning methods. However, the solvent cracking method requires a large amount of organic solvent, is not environment-friendly, and requires higher temperature for cracking caprolactam or adipic acid or hexamethylenediamine, and has high energy consumption and high cost; the mechanical crushing and cleaning method is often matched with a physical recycling method to separate and recycle carpets through mechanical shearing force crushing treatment, and the method has the advantages of simple required equipment and low recycling cost, but sometimes has the problem of low recycling efficiency.
The physical recycling method generally separates the carpets according to the physical property differences of materials to be separated in the waste carpets, such as density, solubility, melting point, thermal decomposition temperature difference and the like, and generally has the advantages of simple operation method, low energy consumption, low equipment requirement, low carpet recycling cost and the like. There are a great deal of literature reports about carpet treatment by physical methods, such as patents (CN 112356338A, CN101838864 a) for separation according to density, but the methods of hydraulic sorting and pneumatic sorting have the disadvantages that the classification index is seriously affected when the feeding parameters are unstable, resulting in poor separation effect; for another example, according to the method of separation according to solubility difference (CN 101631911A, CN111892743A, CN105713229A, CN109810284A, US5916410, CN111607123 a), patent CN101631911a (homologous patent US9757875B 2) uses a solvent system of terpenes (with other organic cosolvents such as alkanes, monohydric alcohols, ketones, etc.) to dissolve polyolefin substances in the carpet, and separates out the terpenes by distillation, and the materials not dissolved by the terpenes such as nylon are also separated out, and the terpenes are used as solvents, thus having the advantage of green environmental protection; the patent CN111892743A phenol-toluene solvent system is heated to dissolve polyamide waste, water is added to precipitate polyamide solid, and phenol can make nylon end-capped for the second time, and the used solvent system has the advantages of low volatilization, low stimulation, no corrosion and the like.
Although there are also patents which provide better separation methods, the solvents used often have corresponding disadvantages, for example, patent CN105713229a describes a method for separating nylon 66 from nylon 6 in polyamide insulation strips using a mixture of organic solvents (concentrated hydrochloric acid, a methanol saturated solution of calcium chloride, m-cresol, formic acid,Diethylene glycol) to dissolve polyamide insulation bar particles, by adjusting H by taking advantage of the difference in solubility of nylon 66 and nylon 6 in hydrochloric acid + The concentration is carried out on the precipitation treatment of the suction filtration filtrate, and nylon 66 and nylon 6 in the polyamide heat insulation strip are accurately separated; and patent CN109810284 a-the polyamide is dissolved by using strong proton solvents (formic acid, hydrochloric acid, acetic acid and water) and forming hydrogen bonds with strong polar hydrogen ions and acid radical ions, and the PA12 precipitate is centrifugally separated. However, this separation method has the disadvantages: the acid waste water is subjected to neutralization treatment by a large amount of strong alkali, and the amide bond in the strong acid environment can be hydrolyzed to reduce the molecular weight of the recovered polyamide.
US patent US5230473 disintegrates carpet separation by repeatedly using high pressure fluid (from air, water, hot air, steam, chemical solution) and repeatedly peeling the emulsion/filler bonding system using a rotating element, but also has the disadvantages of high energy consumption and high use amount of organic solvent; patent CN200710053225.3 and CN200710053667.8 adopt an alcohol dissolution method to dissolve PA11 and PA12, but are difficult to apply to nylon 6 and nylon 66 with strong hydrogen bond polarity; patent CN111607123a describes a method for recovering nylon/polyolefin composite membrane by using ionic liquid, which uses the solubility difference of ionic liquid to nylon and polyolefin, the ionic liquid can dissolve nylon and indissolvable polyolefin, and separate and recover polyolefin and nylon, but the ionic liquid is expensive, difficult to purify and separate, toxic and not really a 'green' solvent.
The choline eutectic solvent (DES) is formed by combining anions of choline salt and a complexing agent through certain interaction, such as hydrogen bonds, covalent bonds and the like. The choline eutectic solvent has the characteristics of being more outstanding than ionic liquid, such as wide dissolution characteristics, easily available raw materials, low toxicity, biodegradability, recycling, low price and the like, and is widely applied to the fields of lubrication, functional material preparation, electrochemistry, organic synthesis, biomass catalytic conversion and the like.
However, there is currently no report of using DES to dissolve nylon materials in carpets for carpet recycling.
Disclosure of Invention
In view of the above, the invention aims to provide a method for recycling waste carpets, which dissolves nylon fibers in carpets through a eutectic solvent system, thereby achieving the purpose of recycling waste carpets and solving the defects in the prior art.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
the method for recycling the waste carpets specifically comprises the following steps:
(1) Pretreatment of waste carpets
Sorting the waste carpets to obtain nylon carpets, and sequentially washing and drying the nylon carpets; firstly stripping the carpet surface nylon fiber and the backing material, and then mechanically rolling the backing material to obtain the completely stripped polyolefin backing cloth;
(2) Waste carpet crushing treatment
Mechanically crushing the carpet surface nylon fiber and the polyolefin backing cloth to obtain a crushed carpet;
(3) Recovery of polyolefin materials
Preparing a choline chloride eutectic solvent, adding crushed carpets, heating for reflux treatment, filtering to obtain filtrate for dissolving nylon materials and undissolved polyolefin, washing undissolved polyolefin with water, and drying to obtain pure polyolefin materials; wherein the raw materials of the choline chloride eutectic solvent are choline chloride and urea or choline chloride and diglycol;
(4) Recycled nylon material
Filtering the filtrate for dissolving the nylon material with a stainless steel screen, then heating to remove solvent and separate, washing the obtained nylon material with water, drying, and recovering to obtain pure nylon material;
(5) Recovery of solvent
Collecting choline chloride eutectic solvent used in the reaction, removing solvent, separating, and recycling.
In the invention, the separation and recovery principle of the choline chloride eutectic solvent is as follows:
[HOC 2 H 4 N(CH 3 ) 3 ] + +[Cl] - +n(NH 2 CONH 2 )→(NH 2 CONH 2 ) n [Cl] - +[HOC 2 H 4 N(CH 3 ) 3 ] + ；
[HOC 2 H 4 N(CH 3 ) 3 ] + +[Cl] - +n(HOC 2 H 4 OC 2 H 4 OH)→(HOC 2 H 4 OC 2 H 4 OH) n [Cl] - +[HOC 2 H 4 N(CH 3 ) 3 ] + 。
Cl - the reaction product forms an integral anion with urea or diethylene glycol through hydrogen bonding, the interaction with choline cations is reduced, the choline cations can be used as electron acceptors, oxygen atoms in nylon amide bonds can be used as electron donors, the electron donors are combined with the electron acceptors to form hydrogen bonding interactions, the hydrogen bonding inside nylon is weakened, and meanwhile, the eutectic solvent and the nylon have hydrogen bonding interactions (Comp controller Chem,2012, 987:57-61).&Guangdong chemical industry, 2013,15 (40), 208), has weak polar properties similar to nylon molecules, presumably dissolving nylon according to the "similar miscibility" principle. Because the polypropylene has no polar functional group, the polypropylene can not be compatible with the choline chloride eutectic solvent, thereby achieving the aim of separating the nylon material from the polypropylene material in the carpet.
Further, in the step (1), the waste carpet includes a carpet, grey cloth or nylon carpet leftover material, and the waste carpet has a structure of a block carpet, a roll-over broad carpet, a tufted carpet, a needled carpet or a hand-woven carpet.
The technical scheme has the beneficial effects that the carpet containing nylon materials can be dissolved for carpets of different types, and the subsequent steps are convenient to separate from other substances in the carpets.
Further, in the step (2), the equipment for mechanical crushing is a crusher, a shearing machine, a grinder or a pendulum suspension mill; further, the crusher is a hammer crusher, a jaw crusher, a twin roll crusher, a vertical composite crusher or an inertia cone crusher.
The technical proposal has the beneficial effects that the carpet is fully crushed into a certain size by mechanical crushing, which is beneficial to the dissolution of the eutectic solvent.
Further, in the above step (2), the size of the crushed carpet is 0.1 to 1.0mm, preferably 0.1 to 0.5mm.
The technical proposal has the beneficial effects that the carpet is fully crushed into a certain size, so as to be convenient for being fully dissolved in the choline chloride eutectic solvent.
Further, in the step (3), the mass ratio of the choline chloride to the urea is 1 (1.5-2.5), preferably 1:2; the mass ratio of the choline chloride to the diglycol is 1 (1.0-2.5), and is preferably 1:2; the mass ratio of the choline chloride eutectic solvent to the broken carpet is (8-15) to (1-2).
The technical proposal has the advantages that the proper viscosity (0.01-1 Pa.s) is achieved by adjusting the raw material proportion of the choline eutectic solvent, the fluidity of the choline eutectic solvent is ensured, and the choline eutectic solvent can be fully contacted with the carpet for dissolution.
Further, in the step (3), a phenolic solvent is further included; the phenolic solvent is at least one of phenol, o-cresol, m-cresol and p-cresol, preferably phenol or p-cresol; the mass ratio of the phenolic solvent to the choline chloride eutectic solvent is (0.5-1) to (7-8).
The technical proposal has the beneficial effects that the phenolic solvent plays an auxiliary dissolving role on the choline chloride eutectic solvent, and the dissolving time can be shortened to a certain extent.
Further, in the step (3), the temperature of the heat reflow treatment is 65-95 ℃, preferably 70-90 ℃; the time of the heat reflux treatment is 5 to 24 hours, preferably 15 to 24 hours.
The technical scheme has the advantages that the choline chloride eutectic solvent can be fully contacted with the crushed carpet through the heating reflux treatment, the Van der Waals force among nylon molecules is destroyed, the solvent volatilization loss can be reduced through the reflux treatment, and the cost is saved.
Further, in the step (3), the filtration is a filter screen filtration, a filter membrane filtration, a centrifugal filtration, a tube filtration, an ultra-frequency vibration filtration, a vacuum filtration or a reduced pressure filtration.
The technical scheme has the advantage that undissolved polyolefin can be separated through filtration treatment.
Further, in the step (4), the method of heating to remove solvent and separate is a conventional natural evaporation, wiped film evaporation, distillation, vacuum pressurization method or flash tank method; the temperature is set to be lower than the nylon melting point temperature (PA 6 220 ℃ C., PA66 260 ℃ C.), preferably 90-120 ℃ C.
The technical scheme has the advantages that the nylon material can be effectively dissolved at low temperature and no pressure environment through crushing treatment, the eutectic solvent with adjustable proportion and low-temperature reflux dissolution, the polyolefin material insoluble in the eutectic solvent is separated from the nylon material, the purpose of high-efficiency separation and recovery is achieved, and the recovery rate of the nylon material is high. Moreover, the choline chloride eutectic solvent disclosed by the invention is environment-friendly, and has the advantages of low volatility and convenience in recycling compared with the strongly acidic volatile solvent in the prior art.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention adopts choline chloride eutectic solvent to dissolve nylon material in carpet by forming hydrogen bond interaction with amide bond, but not polypropylene component, thereby achieving the separation purpose.
2. The choline chloride eutectic solvent can weaken the hydrogen bond of nylon 6 or nylon 66 through strong hydrogen bond interaction to effectively dissolve, and overcomes the limitation that the method of alcohol dissolution in the prior art cannot be applied to nylon 6 and nylon 66 with strong hydrogen bond polarity.
3. Unlike available patent, which has nylon material dissolved by forming hydrogen bond with strong acid or polar hydrogen ion and acid radical ion, the present invention has the advantages of low volatility, low irritation, low dissolving temperature, being recyclable and being recyclable.
4. Compared with the prior art that ionic liquid is adopted as solvent to dissolve and separate nylon and polypropylene in carpet, the choline chloride eutectic solvent used in the invention has the advantages of low cost, no toxicity, more environment protection and the like.
5. The recycling method can efficiently and safely recycle the waste carpets, reduce the resource waste and reduce the environmental pollution.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
The method for recycling the waste carpets specifically comprises the following steps:
(1) Pretreatment of waste carpets
Sorting the waste carpets to obtain nylon 6 carpets, and sequentially washing and drying to remove impurities; firstly, roughly stripping the nylon 6 fiber and the backing material of the carpet surface by scissors, and then mechanically rolling the backing material to remove a bottom hard rubber layer (namely styrene butadiene rubber and calcium carbonate) so as to obtain the completely stripped polyolefin backing cloth;
(2) Waste carpet crushing treatment
Adding the carpet surface nylon 6 fiber and the polyolefin backing cloth into a hammer crusher for mechanical crushing to obtain a crushed carpet with the size of 0.1-0.5 mm;
(3) Recovery of polyolefin materials
Uniformly stirring and mixing choline chloride and urea according to a mass ratio of 1:2, preparing a choline chloride/urea eutectic solvent, adding phenol and choline chloride eutectic solvents according to a mass ratio of 0.8:7, mixing the choline chloride/urea eutectic solvent and a broken carpet according to a mass ratio of 15:1, heating and refluxing at 90 ℃ for 24 hours to dissolve nylon 6 materials in the broken carpet, filtering by a filter screen with a pore diameter of less than 100 mu m to obtain filtrate of dissolved nylon materials and undissolved polyolefin, washing undissolved polyolefin with water, and drying to obtain pure polyolefin materials;
(4) Recycled nylon material
Transferring the filtrate for dissolving the nylon 6 material into distillation equipment, distilling at 120 ℃, washing the obtained nylon material with water, drying, and recovering to obtain pure nylon 6 material;
(5) Recovery of solvent
Collecting the choline chloride/urea eutectic solvent used in the reaction, removing the solvent, separating, and recycling.
Example 2
The method for recycling the waste carpets specifically comprises the following steps:
(1) Pretreatment of waste carpets
Sorting the waste carpets to obtain nylon 66 carpets, and sequentially washing and drying the nylon 66 carpets to remove impurities; firstly, roughly stripping the nylon 66 fiber and the backing material of the carpet surface by scissors, and then mechanically rolling the backing material to remove the bottom hard rubber layer (namely styrene butadiene rubber and calcium carbonate) so as to obtain the completely stripped polyolefin backing cloth;
(2) Waste carpet crushing treatment
Adding the carpet surface nylon 66 fiber and the polyolefin backing cloth into a hammer crusher for mechanical crushing to obtain a crushed carpet with the size of 0.2-0.6 mm;
(3) Recovery of polyolefin materials
Uniformly stirring and mixing choline chloride and urea according to a mass ratio of 1:1.5, preparing a choline chloride/urea eutectic solvent, mixing the choline chloride/urea eutectic solvent and a broken carpet according to a mass ratio of 2:1, heating and refluxing for 20 hours at 85 ℃ to dissolve nylon 66 materials in the broken carpet, centrifugally filtering at a rotating speed of 3000r/min to obtain filtrate for dissolving the nylon materials and undissolved polyolefin, washing the undissolved polyolefin with water, and drying to obtain pure polyolefin materials;
(4) Recycled nylon material
Transferring the filtrate for dissolving the nylon 66 material into vacuum pressurizing equipment, carrying out vacuum pressurizing under the conditions of 300mmHg vacuum degree and 5r/min rotating speed of a rotary drum, washing the obtained nylon material with water, drying, and recovering to obtain a pure nylon 66 material;
(5) Recovery of solvent
Collecting the choline chloride/urea eutectic solvent used in the reaction, removing the solvent, separating, and recycling.
Example 3
The method for recycling the waste carpets specifically comprises the following steps:
(1) Pretreatment of waste carpets
Sorting the waste carpets to obtain nylon 6 carpets, and sequentially washing and drying to remove impurities; firstly, roughly stripping the nylon 6 fiber and the backing material of the carpet surface by scissors, and then mechanically rolling the backing material to remove a bottom hard rubber layer (namely styrene butadiene rubber and calcium carbonate) so as to obtain the completely stripped polyolefin backing cloth;
(2) Waste carpet crushing treatment
Adding the carpet surface nylon 6 fiber and the polyolefin backing cloth into a hammer crusher for mechanical crushing to obtain a crushed carpet with the size of 0.3-1.0 mm;
(3) Recovery of polyolefin materials
Uniformly stirring and mixing choline chloride and diglycol according to a mass ratio of 1:2, preparing a choline chloride/urea eutectic solvent, mixing the choline chloride/diglycol eutectic solvent and a broken carpet according to a mass ratio of 7:5, heating and refluxing at 80 ℃ for 18 hours to dissolve nylon 6 materials in the broken carpet, filtering by using an over-frequency vibration filter membrane with a vibration frequency of 50Hz to obtain filtrate for dissolving the nylon materials and undissolved polyolefin, washing the undissolved polyolefin with water, and drying to obtain pure polyolefin materials;
(4) Recycled nylon material
Transferring the filtrate for dissolving the nylon 6 material into distillation equipment, distilling at 95 ℃, washing the obtained nylon material with water, drying, and recovering to obtain pure nylon 6 material;
(5) Recovery of solvent
Collecting the choline chloride/diglycol eutectic solvent used in the reaction, removing the solvent, separating, and recycling.
Performance testing
The recovery rates of nylon material and polyolefin material in examples 1-3 were separately counted and calculated. The results are shown in Table 1.
TABLE 1 examples 1-3 recovery of Nylon and polyolefin materials
As is clear from Table 1, the recovery rate of nylon material and the recovery rate of polyolefin material in the recovery method of the present invention were both 90% or more. Among them, embodiment 1 is the best embodiment.
The experiment shows that the recycling method can efficiently and safely recycle the waste carpets, reduce the resource waste and reduce the environmental pollution.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (5)
1. The method for recycling the waste carpets is characterized by comprising the following steps of:
(1) Pretreatment of waste carpets
Sorting the waste carpets to obtain nylon carpets, and sequentially washing and drying the nylon carpets; firstly stripping the carpet surface nylon fiber and the backing material, and then mechanically rolling the backing material to obtain the completely stripped polyolefin backing cloth;
(2) Waste carpet crushing treatment
Mechanically crushing the carpet surface nylon fiber and the polyolefin backing cloth to obtain a crushed carpet;
(3) Recovery of polyolefin materials
Preparing a choline chloride eutectic solvent, adding crushed carpets, heating for reflux treatment, filtering to obtain filtrate for dissolving nylon materials and undissolved polyolefin, washing undissolved polyolefin with water, and drying to obtain pure polyolefin materials;
the raw materials of the choline chloride eutectic solvent are choline chloride and urea or choline chloride and diglycol; the mass ratio of the choline chloride to the urea is 1 (1.5-2.5); the mass ratio of the choline chloride to the diglycol is 1 (1.0-2.5); the mass ratio of the choline chloride eutectic solvent to the broken carpet is (8-15) (1-2);
also comprises phenolic solvent; the phenolic solvent is at least one of phenol, o-cresol, m-cresol and p-cresol; the mass ratio of the phenolic solvent to the choline chloride eutectic solvent is (0.5-1) (7-8);
the temperature of the heating reflux treatment is 65-95 ℃ and the time is 5-24 hours;
(4) Recycled nylon material
Filtering the filtrate for dissolving the nylon material with a stainless steel screen, then heating to remove solvent and separate, washing the obtained nylon material with water, drying, and recovering to obtain pure nylon material;
the heating desolventizing and separating treatment method is conventional natural evaporation, wiped film evaporation, distillation, vacuum pressurizing method or flash tank method, and the temperature is 90-120 ℃;
(5) Recovery of solvent
Collecting choline chloride eutectic solvent used in the reaction, removing solvent, separating, and recycling.
2. The method for recycling waste carpeting according to claim 1, wherein in the step (1), the waste carpeting comprises carpeting, grey cloth or nylon carpet leftover materials with main components of nylon materials, and the structure is a block carpet, a roll-over broadloom carpet, a tufted carpet, a needled carpet or a hand-woven carpet.
3. The method according to claim 1, wherein in the step (2), the mechanical crushing equipment is a crusher, a shearing machine, a grinder or a pendulum suspension mill; the crusher is a hammer crusher, a jaw crusher, a twin roll crusher, a vertical composite crusher or an inertia cone crusher.
4. The method according to claim 1, wherein in the step (2), the size of the crushed carpet is 0.1 to 1.0mm.
5. The method for recycling waste carpeting according to claim 1, wherein in the step (3), the filtration is a filter screen filtration, a filter membrane filtration, a centrifugal filtration, a tube filtration, an ultra-frequency vibration filtration, a vacuum filtration or a reduced pressure filtration.
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